2008 INFINITI FX35 intake

DTC P0137, P0157 HO2S2EC-245
< SERVICE INFORMATION > [VQ35DE]
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DTC P0137, P0157 HO2S2
Component DescriptionINFOID:0000000001326074
The heated oxygen sensor 2 (HO2S2), after three way catalyst 1,
monitors the oxygen level in the exhaust gas on each bank.
Even if switching characteristics of the air fuel ratio (A/F) sensor 1
are shifted, the air-fuel ratio is controlled to stoichiometric, by the sig-
nal from the heated oxygen sensor 2.
This sensor is made of ceramic zirconia. The zirconia generates volt-
age from approximately 1V in richer conditions to 0V in leaner condi-
tions.
Under normal conditions the heated oxygen sensor 2 is not used for
engine control operation.
CONSULT-III Reference Val
ue in Data Monitor ModeINFOID:0000000001326075
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000001326076
The heated oxygen sensor 2 has a much longer switching time
between rich and lean than the air fuel ratio (A/F) sensor 1. The oxy-
gen storage capacity of the three way catalyst 1 causes the longer
switching time. To judge the malfunctions of heated oxygen sensor
2, ECM monitors whether the maximum voltage of the sensor is suf-
ficiently high during the various driving condition such as fuel-cut.
DTC Confirmation ProcedureINFOID:0000000001326077
NOTE:
If DTC confirmation Procedure has been previously conduc ted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
WITH CONSULT-III
TESTING CONDITION:
For better results, perform DTC WORK SUPPORT at a temperature of 0 to 30 °C (32 to 86 °F).
SEF327R
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 (B1)
HO2S2 (B2)  Revving engine from idle to 3,000 rpm quickly after the following conditions
are met
- Engine: After warming up
- Keeping the engine speed between 3,500 and 4,000 rpm for 1 minute and
at idle for 1 minute under no load 0 - 0.3V
←→ Approx. 0.6 - 1.0V
HO2S2 MNTR(B1)
HO2S2 MNTR(B2) LEAN
←→ RICH
SEF259VA
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0137
0137
(Bank 1) Heated oxygen sensor 2
circuit low voltage The maximum voltage from the sensor is not
reached to the specified voltage.  Harness or connectors
(Heated oxygen sensor 2 circuit is open
or shorted)
 Heated oxygen sensor 2
 Fuel pressure
 Fuel injector
 Intake air leaks
P0157
0157
(Bank 2)
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

DTC P0139, P0159 HO2S2EC-265
< SERVICE INFORMATION > [VQ35DE]
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DTC P0139, P0159 HO2S2
Component DescriptionINFOID:0000000001326092
The heated oxygen sensor 2 (HO2S2), after three way catalyst 1,
monitors the oxygen level in the exhaust gas on each bank.
Even if switching characteristics of the air fuel ratio (A/F) sensor 1
are shifted, the air-fuel ratio is controlled to stoichiometric, by the sig-
nal from the heated oxygen sensor 2.
This sensor is made of ceramic zirconia. The zirconia generates volt-
age from approximately 1V in richer conditions to 0V in leaner condi-
tions.
Under normal conditions the heated oxygen sensor 2 is not used for
engine control operation.
CONSULT-III Reference Val
ue in Data Monitor ModeINFOID:0000000001326093
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000001326094
The heated oxygen sensor 2 has a much longer switching time
between rich and lean than the air fuel ratio (A/F) sensor 1. The oxy-
gen storage capacity before the three way catalyst 1 causes the
longer switching time. To judge the malfunctions of heated oxygen
sensor 2, ECM monitors whether the switching response of the sen-
sor's voltage is faster than specified during the various driving condi-
tion such as fuel-cut.
DTC Confirmation ProcedureINFOID:0000000001326095
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
WITH CONSULT-III
TESTING CONDITION:
For better results, perform “DTC WORK SUPPORT” at a temperature of 0 to 30 °C (32 to 86 °F).
SEF327R
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 (B1)
HO2S2 (B2)  Revving engine from idle to 3,000 rpm quickly after the following conditions
are met
- Engine: After warming up
- Keeping the engine speed between 3,500 and 4,000 rpm for 1 minute and
at idle for 1 minute under no load 0 - 0.3V
←→ Approx. 0.6 - 1.0V
HO2S2 MNTR(B1)
HO2S2 MNTR(B2) LEAN
←→ RICH
SEF302U
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0139
0139
(Bank 1) Heated oxygen sensor 2
circuit slow response It takes more time for the sensor to respond be-
tween rich and lean than the specified time.  Harness or connectors
(Heated oxygen sensor 2 circuit is open
or shorted)
 Heated oxygen sensor 2
 Fuel pressure
 Fuel injector
 Intake air leaks
P0159
0159
(Bank 2)
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

EC-274
< SERVICE INFORMATION >[VQ35DE]
DTC P0171, P0174 FUEL IN
JECTION SYSTEM FUNCTION
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
On Board Diagnosis LogicINFOID:0000000001326101
With the Air-Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the
theoretical mixture ratio based on the mixture ratio feedback signal from the air fuel ratio (A/F) sensor 1. The
ECM calculates the necessary compensation to corr ect the offset between the actual and the theoretical
ratios.
In case the amount of the compensation value is extrem ely large (the actual mixture ratio is too lean.), the
ECM judges the condition as the fuel injection system malfunction and lights up the MIL (2 trip detection logic).
DTC Confirmation ProcedureINFOID:0000000001609263
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
WITH CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Turn ignition switch ON and select “SELF-LE ARNING CONT” in “WORK SUPPORT” mode with CON-
SULT-III.
4. Clear the self-learning control coefficient by touching “CLEAR”.
5. Start engine. If it is difficult to start engine, the fuel injection system has a malfunction.
Perform the following procedure is advised.
a. Crank engine while depressing accelerator pedal.
b. If engine starts, go to EC-279, "
Diagnosis Procedure".
If engine does not start, check exhaus t and intake air leak visually.
6. Keep engine at idle for at least 10 minutes.
7. Check 1st trip DTC.
8. If 1st trip DTC is detected, go to EC-279, "
Diagnosis Procedure".
If 1st trip DTC is not detected, per forming the following procedure is advised.
a. Turn ignition switch OFF and wait at least 10 seconds.
b. Start engine and drive the vehicle under the similar conditions to (1st trip) Freeze Frame Data for 10 min- utes. Refer to the table below.
Hold the accelerator pedal as steady as possible.
The similar conditions to (1st trip) Freeze Frame Da ta means the vehicle operation that the following con-
ditions should be satisfied at the same time.
Sensor Input signal to ECM ECM function Actuator
Air fuel ratio (A/F) sensor 1 Density of oxygen in exhaust gas
(Mixture ratio fe
edback signal) Fuel injection
control
Fuel injector
DTC No.
Trouble diagnosis
name DTC detecting condition Possible cause
P0171
0171
(Bank 1) Fuel injection system
too lean  Fuel injection system does not operate properly.
 The amount of mixture ratio compensation is too
large. (The mixture ratio is too lean.)  Intake air leaks
 Air fuel ratio (A/F) sensor 1
 Fuel injector
 Exhaust gas leaks
 Incorrect fuel pressure
 Lack of fuel
 Mass air flow sensor
 Incorrect PCV hose connection
P0174
0174
(Bank 2)
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-275
< SERVICE INFORMATION > [VQ35DE]
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9. Check 1st trip DTC.
10. The 1st trip is detected, go to
EC-279, "
Diagnosis Procedure".
WITH GST
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Disconnect mass air flow sensor harness connector.
4. Restart engine and let it idle for at least 5 seconds.
5. Stop engine and reconnect mass air flow sensor harness con-
nector.
6. Select Service $03 with GST. Make sure DTC P0102 is detected.
7. Select Service $04 with GST and erase the DTC P0102.
8. Start engine. If it is difficult to start engine, the fuel injection system has a mal-
function.
Perform the following procedure is advised.
a. Crank engine while depressing accelerator pedal.
b. If engine starts, go to EC-279, "
Diagnosis Procedure".
If engine does not start, check exhaust and intake air leak visually.
9. Keep engine at idle for at least 10 minutes.
10. Check 1st trip DTC.
11. If 1st trip DTC is detected, go to EC-279, "
Diagnosis Procedure".
If 1st trip DTC is not detected, per forming the following procedure is advised.
a. Turn ignition switch OFF and wait at least 10 seconds.
b. Start engine and drive the vehicle under the similar condi tions to (1st trip) Freeze Frame Data for 10 min-
utes. Refer to the table below.
Hold the accelerator pedal as steady as possible.
The similar conditions to (1st trip) Freeze Frame Da ta means the vehicle operation that the following con-
ditions should be satisfied at the same time.
12. Check 1st trip DTC.
13. The 1st trip is detected, go to EC-279, "
Diagnosis Procedure".
Engine speed Engine speed in the freeze frame data ± 400 rpm
Vehicle speed Vehicle speed in the freeze frame data ± 10 km/h (6 MPH)
Engine coolant temperature (T)
condition When the freeze frame data shows lower than 70
°C (158 °F),
T should be lower than 70 °C (158 °F).
When the freeze frame data shows higher than or equal to 70 °C (158 °F),
T should be higher than or equal to 70 °C (158 °F).
PBIB1565E
Engine speed Engine speed in the freeze frame data ± 400 rpm
Vehicle speed Vehicle speed in the freeze frame data ± 10 km/h (6 MPH)
Engine coolant temperature (T)
condition When the freeze frame data shows lower than 70
°C (158 °F),
T should be lower than 70 °C (158 °F).
When the freeze frame data shows higher than or equal to 70 °C (158 °F),
T should be higher than or equal to 70 °C (158 °F).
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-279
< SERVICE INFORMATION > [VQ35DE]
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: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
Diagnosis ProcedureINFOID:0000000001326104
1.CHECK EXHAUST GAS LEAK
1. Start engine and run it at idle.
2. Listen for an exhaust gas leak before three way catalyst 1.
OK or NG
OK >> GO TO 2.
NG >> Repair or replace.
2.CHECK FOR INTAKE AIR LEAK
TER- MI-
NAL
NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
24 L A/F sensor 1 heater
(bank 2) [Engine is running]

Warm-up condition
 Idle speed Approximately 5V
40
41
42 LG
B
P Fuel injector No. 6
Fuel injector No. 4
Fuel injector No. 2 [Engine is running]

Warm-up condition
 Idle speed NOTE:
The pulse cycle changes depending on rpm
at idle BATTERY VOLTAGE
(11 - 14V)
[Engine is running]
 Warm-up condition
 Engine speed: 2,000 rpm BATTERY VOLTAGE
(11 - 14V)
57 G A/F sensor 1 (bank 2) [Engine is running]

Warm-up condition
 Idle speed Approximately 2.6V
58 Y Approximately 2.3V
76 P Approximately 3.1V
77 BR Approximately 2.3V
PBIB1584E
SEC984C
SEC985C
PBIB1922E
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

EC-280
< SERVICE INFORMATION >[VQ35DE]
DTC P0171, P0174 FUEL IN
JECTION SYSTEM FUNCTION
1. Listen for an intake air leak after the mass air flow sensor.
2. Check PCV hose connection.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace.
3.CHECK AIR FUEL RATIO (A/F) SE NSOR 1 INPUT SIGNAL CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect corresponding air fuel ration (A/F) sensor 1 harness connector.
3. Disconnect ECM harness connector.
4. Check harness continuity between the following terminals. Refer to Wiring Diagram.
5. Check harness continuity between the following terminals and ground. Refer to Wiring Diagram.
6. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK FUEL PRESSURE
1. Release fuel pressure to zero. Refer to EC-87, "
Fuel Pressure Check".
2. Install fuel pressure gauge and check fuel pressure. Refer to EC-87, "
Fuel Pressure Check".
A/F sensor 1 terminal ECM terminal
Bank 1 116
275
535
656
Bank 2 176
277
557
658
Continuity should exist.
Bank 1 Bank 2
A/F sensor 1 terminal ECM terminal A/F sensor 1 terminal ECM terminal 116176
275277
535557
656658
Continuity should not exist.
PBIB2190E
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
EC-289
< SERVICE INFORMATION > [VQ35DE]
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: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
Diagnosis ProcedureINFOID:0000000001326108
1.CHECK EXHAUST GAS LEAK
1. Start engine and run it at idle.
2. Listen for an exhaust gas leak before three way catalyst 1.
OK or NG
OK >> GO TO 2.
NG >> Repair or replace.
2.CHECK FOR INTAKE AIR LEAK
TER- MI-
NAL
NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
24 L A/F sensor 1 heater
(bank 2) [Engine is running]

Warm-up condition
 Idle speed Approximately 5V
40
41
42 LG
B
P Fuel injector No. 6
Fuel injector No. 4
Fuel injector No. 2 [Engine is running]

Warm-up condition
 Idle speed NOTE:
The pulse cycle changes depending on rpm
at idle BATTERY VOLTAGE
(11 - 14V)
[Engine is running]
 Warm-up condition
 Engine speed: 2,000 rpm BATTERY VOLTAGE
(11 - 14V)
57 G A/F sensor 1 (bank 2) [Engine is running]

Warm-up condition
 Idle speed Approximately 2.6V
58 Y Approximately 2.3V
76 P Approximately 3.1V
77 BR Approximately 2.3V
PBIB1584E
SEC984C
SEC985C
PBIB1922E
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

EC-290
< SERVICE INFORMATION >[VQ35DE]
DTC P0172, P0175 FUEL IN
JECTION SYSTEM FUNCTION
Listen for an intake air leak after the mass air flow sensor.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace.
3.CHECK AIR FUEL RATIO (A/F) SE NSOR 1 INPUT SIGNAL CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect corresponding A/F sensor 1 harness connector.
3. Disconnect ECM harness connector.
4. Check harness continuity between the following terminals. Refer to Wiring Diagram.
5. Check harness continuity between the following terminals and ground. Refer to Wiring Diagram.
6. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK FUEL PRESSURE
1. Release fuel pressure to zero. Refer to EC-87, "
Fuel Pressure Check".
2. Install fuel pressure gauge and check fuel pressure. Refer to EC-87, "
Fuel Pressure Check".
Bank 1A/F sensor 1 terminal ECM terminal
116
275
535
656
Bank 2 176
277
557
658
Continuity should exist.
Bank 1 Bank 2
A/F sensor 1 terminal ECM terminal A/F sensor 1 terminal ECM terminal 116176
275277
535557
656658
Continuity should not exist.
PBIB2190E
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C